1. Field of the Invention
The invention relates in general to a semiconductor device and a method for manufacturing the same, and more particularly to a semiconductor device having a gate all around (GAA) structure and a method for manufacturing the same.
2. Description of the Related Art
Various novel semiconductor structures have been proposed with the progress of the semiconductor manufacturing technology, by which the device size is gradually reduced, in order to solve the problem of the physical limitation accompanying therewith. Taking a memory structure as an example, an equivalent width of a channel is increased using a three-dimensional structure. A fin gate memory including a double gate structure or a tri-gate structure is an example of novel memory structure, so that a memory device having a small size still can generate a significant working current.
With the further reduction of the device size, however, the current memory structure still cannot overcome the problem of the caused physical limitation. For example, the control of the gate for switching the channel current encounters a bottleneck. Thus, it is necessary to find a better structure of a semiconductor device so that the semiconductor device having the small size still can possess the good operating property.